Core vent



Sept. 20, 1949. c. A. DUDZINSKI CORE VENT Filed Dec. 10, 1947 ATTORNEYSM w M u A C Patented Sept. 20, 1949 CORE VENT Clarence A. Dudzinski,Detroit, Mich., assignor to Ford Motor Company, Dearborn, Mich., acorporation-of Delaware Application December 10, 1947, Serial No.790,895

6 Claims. 1

This invention relates to foundry art generally, and more particularlyto a core vent or sand retainer for use in the mass production of sandcores.

Mass production of foundry cores is conventionally accomplished byforming or molding the core material to the desired shape in a metalcore box. The cores are made from a mixture comprising moist sand and abinding agent, To economically produce the cores under mass productionrequirements, it is essential that the core mixture be rapidly depositedin the core box under sufficient pressure to form a compact and strongcore. This is conventionally accomplished by transporting the sandpneumatically into the core box under considerable pneumatic pressure.As the core box fills with the core mixture, it is necessary to providea means for the rapid escape of the air already in the core box inaddition to the air used in transporting the sand into the core box.Such means must also provide for a minimum retention of the core mixturein the core box.

Efforts to accomplish these objectives have not proven generallysatisfactory. The core vents used in modern foundry production methodsvary widely from a simple screen to complicated and expensive vents.Typical examples of the above structures are described in U. S. Letters.Patents 2,060,350, 2,126,047, 2,176,328, and 2,238,506.

As the air escapes, some core mixture is unavoidably carried through thevent causing considerable abrasive action resulting in a short life ofthe core vent. Inasmuch as there is a considerable number of such corevents on each core box, it is desirable that replacement of worn outvents may be made rapidly, easily, and economically. The core vent, inaddition to the above requirements, must mar the core as little aspossible due to deformation of the .core vent under pneumatic pressure.

It is therefore an object of this invention to provide a core box ventthat is economical in production, highly durable, and eflicient in use.

Other detects and advantages of the invention will become apparent asthe description proceeds, especially when considered in connection withthe drawings in which:

Figure 1 is a side elevation of one cross supporting member.

Figure 2 is a side elevation of a mating cross supporting member.

Figure 3 is a top elevation of the cross members assembled.

Figure 4 is a cross sectional view of the core vent taken on the line4-4 of Figure 5.

Figure 5 is a cross sectional view of the core vent taken on the line 55of Figure 4.

Figure 6 is a cross sectional view of a core vent showing an alternatespring construction.

Reference is now made to the drawings in-whi'ch the reference characterl0 denotes a core vent shell. One end ll of the shell I0 is curvedinwarclly as shown in Figures 5 and 6 for the dual purpose of providinga seat for the crossed supporting members I2 and I3, and also tofacilitate the insertion of the core vent into the cavity provided inthe core box (not shown).

Escape of the air from the core box and -retention of the sand isactually accomplished the resilient spiral spring [4, as shown in Figure4. 'Thisspiral spring I4 is inserted into the shell i0 and is supportedsecurely in the said shell by crossed supporting members 12 and I3, asbest shown in Figure 5. The outer convolutions of said spiral spring l4rest on the shoulders 16 of the cross supporting member.

The cross supporting members l2 and 13,, as shown in Figures 1 and '2,are preferably formed from sheet metal and are so shaped as to givesufficient support to the spiral spring 14- and still permit a rapidescape of air through the vent. It will be noted that slots I1 and I8are formed in the respective supporting members in such a manner thatwhen supporting member 12 is fitted over supporting member 13 and therespective slots l1 and 18 are engaged, there results a crossedsupporting member the planes of which are 'ap-' proximately apart, asshown in Figure '3. Similar curved depressions [9 and 2| are provided inthe upper portion of each of the crossed supporting members. Thesedepressions permit an oscillating movement of the spring under thevarying air pressures impressed upon the core vent. These oscillationsrender the spiral spring member self-cleaning by permitting a gradualaxial movement of core particles which become entrapped in theconvolutions of the spring. It will be readily seen that this featureprevents clogging of the vent with the concomitant inefliciency'.

The manufacturing costs of the spiral spring IA are minimized since thecrossed supporting members 12 and I3 eliminate the necessity oi having atightly wound center convolution. In many core vent constructions otherthan that described herein, the spring must have a tightly wound centerconvolution so that the openingv between the inner spring convolutionswill be small enough to retain the core mixture while permitting therapid escape of air. If the opening between the center convolutions ofthe spring are too large there would be a resultant sand blast effectthrough the opening and-a consequentshort life of the spring due to theabrasive wear caused by the rapid flow of air and core mixture throughthe opening. There would also be a considerable loss of core mixture,and a consequent inefficiency of the core vent. The cost of a springhaving tightly wound center convolutions is high due to the time andskill required to wind a satisfactory spring.

The spring construction contemplated by this invention need not havesuch a tightly wound center convolution, because the opening betweencenter convolutions of the spring are partially blocked by the crossedsupporting member, The opening between the center convolutions of thespring is actually broken up into four segmental openings that permitthe escape of the air, but will retain the core mixture. Thisconstruction has proven highly efficient and is economical to produce.

It will be noted that the bottom corners of the respective crossedSupporting members are rounded to facilitate easy and accuratepositioning of the crossed supporting members in the core vent shell.

alternate spring construction is shown in Figure 6, in which the spring22 has a vaulted structure. Such vaulting of the spiral spring permits awider range of oscillation, and a resultant more rapid escape of thesmall amounts of sand that may be entrapped in the spring. Inwardmovement of the spring under the pressure of the escaping air is limitedby the arcuate depressions of the crossed supporting members.

It will be noted that the above described core vent constructionconsists of elements that may be rapidly and economically producedwithout the necessity of any special machinery by utilizing machineryalready available in any machine shop. The core vent shell may beproduced from tube stockcut to the'desired length. The cross supportingmembers are preferably stamped from sheet steel of the proper gauge. Thespiral spring is-easilywound from fiat spring stock on any lathe;

Longer life may be imparted to the spring and crossed supporting membersby coating these parts with a latex emulsion. It has been found that arubber emulsion coating on parts subjected to the abrasive action ofsaid particles appreciably lengthens the usable life of such coatedarticles without in any way impairing their efficiency.

While the spring construction described and shown. in this specificationis rectangular in crossed section, it will be understood that there aremany possible types of spring constructions that could be satisfactorilyemployed. An example of such possible construction would be a resilientspiral spring having a circular crossed section.

It will be understood that this invention is not to'be limited to theexact structure shown and described, but that various changes andmodifications may be made without departin from thespirit and scope ofthe invention as defined in the appended claims.

What is claimed is: 7

v1. .Acore vent adapted for use in a core box comprising an outer shell,a resilient spiral spring mounted in said shell, said spiral springhaving its axis substantially parallel to the axis of the shell, andcrossed supporting members within the shell and adapted to support saidspiral spring. 2. A core vent adapted for use in a core box comprising atubular outer shell, a resilient spiral,

spring mounted within said shell, said spinal 10 spring having its axissubstantially parallel to the axis of the shell and two crossedsupporting members within the shell, said crossed supporting membershaving upper and lower edges, an arcuate portion cut out of said upperedges and forming a concave surface and forming shoulders near the shellperiphery, said shoulders supportin the outer convolutions of the spiralspring.

3. A core vent adapted for use in. a core box comprising a tubular'outershell, a resilient flat spiral spring mounted therein, said fiat spiralspring having its axis substantially parallel to the axis of the shell,and two crossed supporting members within the shell and having upper andlower edges, one of said cross supporting members having a slot cutupwardly from said lower edge and intermediate the sides, the other ofsaid supporting members" having a slot cut downwardly from the upperedge and intermediate the sides, said slotsbeing interengaged to form' across shaped supporting unit, and having shoulders formed on saidsupporting members adjacent the periphery of the shell to support theouter convolutions of said'spiral spring.

4.'A core vent adapted for use in a core bo'x' comprising a tubularouter shell, a resilient vaulted spiral spring mounted therein, saidvaulted spiral spring having its axis substantially parallel to the axisof the shell and two crossed supporting members within the shell, saidcrossed supporting members havin similar arcuate portions cut outtherefrom, said'arcuate cutout portion forming shoulders, said shoulderssupport-.

ing the outer convolutions of said vaultedspiral spring.

5. A core vent adapted for use in a core box comprising a tubular outershell, a resilient spiral spring mounted therein, said spiral spring andtubular shell being substantially'coaxial, and two crossed supportinmembers, said crossed supporting members having similar arcuate portionsout out therefrom forming a concave surface and.

forming shoulders near the shell periphery, said shoulders supportingthe outer convolutions of the spiral spring. 7

6. A core vent adapted for use in a core box comprising a tubular outershell, a resilient spiral spring mounted within one end ofv said shelland 7 having its axis substantiallycoincident with the shell axis, and apair of slotted supporting members interengaged at substantially rightangles, the eye of the spiral resilient spring being arranged tobesupported by the intersection of the supportin members whereby thefiltering action of the spiral spring is aided by the partial closure bythe eye by the crossed supporting members.

CLARENCE A; DUDZINSKI.

REFERENCES CITED Thefollowing references are of record in the file ofthis patent:

V'UNITED SITATESIVPATENTS v i Date Number 7 Name 1,480,747 Demmler Jan.15, 1924 1 2,060,350 .Siler Nov. 10, 1936 2,083,148 Coulombe June 8,1937 2,202,379 Hewel May 28, 1940 2,263,974

Rienacker Nov. 25, 1941-

